The anapole moment in scalar quantum electrodynamics

TL;DR

This paper investigates the anapole moment of charged scalar particles in scalar quantum electrodynamics, revealing it is gauge dependent, non-renormalizable, and vanishes on-shell, with implications for its physical observability.

Contribution

It provides a model-independent analysis of the scalar particle's anapole moment using effective Lagrangian and one-loop radiative corrections within SQED, highlighting its gauge dependence and non-renormalizability.

Findings

Anapole moment is gauge dependent and not a physical observable.

The moment is zero when all particles are on-shell.

The interaction responsible is non-renormalizable and radiatively generated.

Abstract

The anapole moment of a charged scalar particle is studied in a model independent fashion, using the effective Lagrangian technique, as well as radiatively within the context of scalar quantum electrodynamics (SQED). It is shown that this gauge structure is characterized by a non renormalizable interaction, which is radiatively generated at the one--loop. It is found that the resulting anapole moment for off-shell particles, though free of ultraviolet divergences, is gauge dependent and thus it is not a physical observable. We also study some of its kinematical limits. In particular, it is shown that its value comes out to be zero when all particles are on--shell.